This invention relates to an actuating arrangement in a single-lever mixing fixture or faucet of the combined volume and proportion control type.
In modern valves of this type the rate of flow is regulated by means of ground ceramic discs, wherein a first disc being mounted in stationary manner in a housing and a second disc being arranged in at least a rotationally movable manner as a control disc and rigidly connected to the actuating member.
According to U.S. Pat. No. 3,433,264 it is known to use such ceramic discs for mixing fixtures. The fixed disc has three axial through bores, one for the inflow of cold water, one for the inflow of hot water and one for the discharge of the mixed water. The control disc has only one connecting recess, which can be continuous, and this recess features a control edge so disposed that, by the rotation of the control disc, the two inflow bores can be opened or closed in a complementary manner in order to thus adjust the mixing ratio from cold to hot water. By a translatory displacement of the control edge, such that it is displaced parallel to itself, the rates of flow can be adjusted at the same mixing ratio.
In such mixer taps there is a problem in making both adjustments with only one actuating member. In German Patent No. 3,219,574 it is proposed to provide an eccentric bearing body centrally disposed in the outer sleeve of the control insert and engaged in a longitudinal groove in a thrust piece or in the control disc itself. On its other side this body is in operative connection with an arm of a bell-crank lever actuated by the operating lever. The control disc is rotated by turning the operating lever about the axis of the control insert to thus adjust the mixing ratio, and the control disc is displaced in a translatory manner in the adjusted rotary position by pivoting the operating lever up and down.
A simplification with respect to the transmission of movement from the lever to the control disc is described in German Patent No. 3,202,392. A rotatable neck part which has a two-piece pivoting part inserted in a transverse bore is available in the control insert. The pivoting part is connected non-rotationally to the lever and, by means of engagement fingers, formed in one piece on each pivoting part, in engagement openings in a guide part mounted non-rotationally and nondisplaceably on the control disc, transmits the rotary and lifting movement to the control disc. A disadvantage is the rotary mounting of the neck part by means of an L-shaped snap ring, engaging from outside. On account of its large diameter correspondingly large frictional forces result, which after wear can make fine regulation impossible. It must be possible for the rotary and displacement movements, which are transmitted by the two engagement fingers from the lever to the guide part, to be accurately executed in an adjustable manner free from play, which after some time can lead to difficulties as a result of the twofold friction with the two engagement fingers. In addition, the two pivoting parts still bear axially against the cartridge housing and produce a further friction spot.
Moreover, the position of the operating lever is predetermined in both of the previously mentioned German patents. It is only possible to preset the maximum temperature and/or the maximum rate of flow by dismantling the cartridge or at least the operating members, because the sensitive articulated joints and friction surfaces must not be accessible to everyone.